From the Field:

Large-scale perspective: Necessity to maintain duck populations

Nesting Success Research 

June 28th, 2008

As we reach the end of June, many hens are attending active nests, but nests numbers across the prairie will likely begin to decline soon as more nests will continue to be hatched or destroyed than are initiated each day. Most of the active nests include gadwall, blue-winged teal, and mallards. Nesting activity will continue to slowly decline from this point. There are currently 393 active duck nests on our study areas, and the fate of these nests will be determined over the next few weeks. Although many of our research areas have received some rainfall it hasn’t been enough to significantly improve the dry wetland conditions that we’ve experienced to date. However, many nests continue to hatch and broods are present as you drive through the pothole country of the Coteau. We have had 64 mallard and 31 pintail nests hatch to date with the best sites being Lostwood site 62 (6 hatched nests), Woodworth site 53 (15 hatched nests) and Goebel site 41 (20 hatched nests).

Although the number of hatched nests is down from years past, the total number of nests is also done as a result of the dry conditions and reduced number of pairs. We’ll see how well the nests have fared overall at the end of the year. This week in From the Field, we will discuss the large spatial scales over which ducks operate throughout the summer and early fall.

With nesting activity winding down, it’s interesting to think about what different components of the population are doing and where they are right now. Many drakes that were paired with hens across our study sites have gone on molt migrations that may have taken then as far as northern Canada. They seek large marshes that provide both the dense emergent cover and food that they’ll need to spend several weeks grounded as they go flightless to re-grow flight feathers. Obviously, nesting hens still attempting to hatch a nest remain on our study sites. However, some females that lost earlier nests may have either migrated some distance to try their luck with a renest or may have headed north for a molt migration of their own. Females with young broods are likely still in the area where they nested but some of the earliest hatched broods will soon be flying and much more mobile. The period between fledging and fall migration is probably the portion of the duck life-cycle that we know the least about. We suspect that some of these birds may move hundreds of miles to take advantage of agricultural foods once harvest of those begins. As a result, an area can be literally crawling with broods during June and July, as our Woodworth crew area currently is, only to be nearly devoid of ducks come August as flighted young birds move to more agriculturally dominated areas to take advantage of energy rich waste grain. Thus, as the nesting season nears completion, birds that originally started the season on our study sites could soon be scattered from Northern Canada to western Minnesota prior to the onset of fall migration. This fact illustrates why Ducks Unlimited must have broad-scale conservation programs to effectively conserve duck populations. Even within the breeding areas, maintaining the large landscapes dominated by grassland from southern South Dakota to northern Saskatchewan remains a priority for DU and requires diverse financial support from across the continent to achieve success.

We hope you will continue to follow along with our work as we gather the final pieces of information from the 2008 nesting season. The next couple of weeks will give us a more complete picture of how production was across our sites. Check back next week to see the happenings on the prairies.